1. Field of the Invention
The present invention relates to a system for modifying non-leaf entries in an OSI (Open System Interconnection) directory of a tree structure, and more particularly to a directory service system using an OSI directory in which entries can be added, modified or removed to or from a directory information tree (DIT).
2. Description of the Related Art
Generally, in order to make it possible to communicate with a destination terminal without knowing a physical arrangement of a network, in an OSI directory, address information and attribute information of the destination terminal are provided on the basis of a logical name thereof, to be informed to a source terminal.
A system for implementing such a directory service as mentioned above usually comprises a directory user agent (DUA), a directory service agent (DSA) and a directory information base (DIB). Entities to be managed by the OSI directory are called objects which are stored as entries in the DIB. A structure in which these entries are arranged in a tree form, based on correlation of the entries with each other, is called a directory information tree (DIT). The highest entry of this DIT is called a root which is connected with lower entries. Of these lower entries, entries which are not connected with further lower entries are called leaf entries, and entries which are not the leaf entries are called non-leaf entries.
The commands which can be used in the above system including the DUA and DSA, include LIST, READ, ADD, MODIFY RDN, and so on. These commands, however, operate only for leaf entries so that the system has a drawback that non-leaf entries cannot be modified through the commands. For example, in a case where a certain section is shifted into another section or a name of the section is changed, because of the change in organization without changing constituent elements of the section, the inherent name of the section as a non-leaf entry must be modified. In this case, the prior art, however, cannot modify the inherent name by a single operation or command.
Prior art related to the OSI directory is described in "OSI--The Directory (ISO9594)" proposed as a Draft International Standard (DIS), and a conventional technique related to a system based on this DIS is disclosed in "Implementation of DIRECTORY (DSA)", JOHOSHORI GAKKAI 38-th 5H-1/2/3. However, this technique is mainly related to the directory (DSA).
Prior art for improving operationality for a directory user is disclosed in, for example, "Proposal of Function for Supporting Directory User", JOHOSHORI GAKKAI 35-th 5U-1. This prior art, however, relates to a search for directories and does not take into consideration improvement of service for users such as addition, modification, etc., of entries for a DIT.